Pressure cooker



Jan. 1940- E. a. GRUNDSTROM ,7

PRESSURE COOKER Filed. Jan. 2, 19 37 2 Sheets-Sheet 1 @MM/M- Jan. 30,1940. E. e. GRUNDSTROM RRESSURE COOKER 2 Sheets-Sheet 2 Filed Jan. 2,1957 w G G. M H

Patented Jan. 30, 1940 UNITED STATES PATENT FFECE PRESSURE COOKERApplication January 2.1937, Serial No. 118,881

Claims.

The present invention relates to improvements in pressure cookers.

The description of the present invention may be prefaced by thestatement that in pressure 5 cookers a vessel containing the material tobe cooked is tightly sealed and heated to a suiflciently hightemperature to cause the genera-.- tion of steam either from themoisture of the material being cooked or from other liquid containedwithin said vessel: After a predetermined pressure has been attained,the vessel may be removed from, the source of heat and the materialtherein subjected to temperature and pressure conditions for apredetermined length of time.

An object of the present invention is to provide an improved pressurecooker having novel means for keeping the vessel closed until apredetermined pressure has been obtained, for giving a signal when saidpredetermined pressure has been reached, and which is readily operableto promote an improved cooking operation.

A further object is to provide a pressure cooker which is perfectly safein the hands of an unskilled operator and which will perform improvedcooking operations even in the hands of such an unskilled operator.

A further object is to provide an improved pressure cooker and a valvetherefor which may be readily assembled and disassembled for convenienceof cleaning, packing and shipping.

A further object is to provide an improved valve for a pressure cooker,which valve has associated therewith a warning whistle and a protectiveby-pass for said whistle.

A further object is to provide an improved pressure cooker having awarning signal which will operate efficiently throughout the entirerange of pressures for which the pressure cooker is designed to operate.

A further object is to provide an improved pressure cooker havingthermometric means for indicating to the operator the relationshipbetween the heat being delivered to said cooker and the setting of thevalve of said cooker whereby said operator may vary the cookingoperation to suit individual conditions.

A further object is to provide an improved pressure cooker having novelfuse means for protecting said cooker against excessive temperatureconditions, which fuse means is provided with guard means for preventingthe spreading of the material within the cooker over the, adjacentregion.

A further object is to provide an improved pressure cooker having simplemeans for preventing jamming of the cover.

A further object is to provide improved sealing means particularly forthe cover of the cooker whereby a. steam-tight joint at said cover may 5be had at all times.

A further object is to provide an improved pressure cooker havingimproved convenience of operation and maintenance.

A further. object is to provide an improved 10 pressure cooker welladapted to meet the needs of ordinary culinary service in the home or ina restaurant or the like.

Further objects will appear as the description proceeds.

Referring to the drawings- Figure' 1 is a view in side elevation of oneembodiment of the present invention;

Figure 2 is a top plan view of the structure shown in Figure 1;

Figure 3 is ,a sectional view on an enlarged scale taken along the planeindicated by the arrows 3& of Figure 1;

Figure 4 is a sectional view on an enlarged scale takenvalong the planeindicated by the g arrows 4-4 of Figure 2;

Figure 5 is a sectional view taken along the plane indicated by thearrows 5--5 of Figure 4;

Figure 6 is a sectional view taken along the plane indicated by thearrows dt of Figure 4; 30 and Figure 7 is a fragmentary view on anenlarged scale illustrating the improved sealing means for the cover ofthe cooker.

The numeral ill indicates a vessel. Said ves- 35 sel i0 is provided withthe elliptical opening l2 bounded by the flange Q3. The cover H isprovidedwith a flange l4 adapted to underlie the flange i3, the gasketI5 being provided between said flange M and said flange 13. As shown inFigure 2, the cover i I is provided with a protuberance l6, preferablylocated at one extremity of the long axis of said cover, adapted to fitinto a corresponding recess in the adjacent portion of the vessel it.Said cover Hat the other extremity of its long axis is provided with theprotuberance ll fitting into a corresponding recess in the vessel it.Said protuberances it and ii are preferably of different sizes, so thatthe u 23 in the cover H.

around the cover, which bead is adapted to embed itself into the gasket,|5 when pressure is exerted between the flanges l3 and I 4, as will beexplained presently, thereby greatly improving 6 the sealing action ofthe gasket I5. A further advantage of the bead Ila is that, since thegasket l5 will in service receive a more or less permanent indentationfrom the bead l'la, said bead and said indentation will constitute indi-10 eating means to insure the same setting of the gasket l5 withreference to the flange I4 at all times. Particularly in cooperationwith the protuberances l6 and H, the flanges l3 and I 4 and the gasketl5 will always have the same setting relative to one another, therebyavoiding the faults of some gaskets that after they lose their originalresiliency they lose their efllciency due to the fact that it is notpossible to always reset them in correct relationship with reference tothe members between which they are to perform their sealing functions.

Mounted centrally cf the cover H is the upstanding threaded stud l8having a handle l8 flxed to its upper extremity. Said handle I 8 is 26preferably of heat insulating material, whereby the cover H and thevessel I 8 may be readily manipulated. Underlying said handle i3 is thespring 20 rotatable about the stud l8 and having v two extremitiesadapted to bear against the upper 80 surface of the flange l3 of thevessel 18. Said extremities of said spring 28 are adapted to abutagainst abutments 2l-2l formed integral with said flange 13 of thevessel Hi. The upper surface of the flange l3 adjacent to the abutments2l-2l may be slightly raised, as indicated by the numerals 22-22,whereby as the spring 28 is turned away from its operative position asshown in Figure 2, said spring 28 will be quickly released withoutbinding or unnecessary scratching a of the surface of the flange l3.

The stud I8 which carries the handle I8 is screw-threaded within thecover H and a spring 23 is provided between the upper side of the coverII and the under side of the spring 28 for 46 holding the extremities ofthe spring 20 away from the cover II when said cover is removed from thevessel Ill. The spring 23, by holding member 28 against the lowerextremity of the handle l9 facilitates the handling of 'the entire .0cover assembly, as the distance between the cover and the lowerextremity of the handle l9 will vary considerably. The handle l9 and itsstud i8 are threaded into the nut 24, which nut is externally threadedwithin the boss 25 extending 5 downwardly from the'under side of thecover-l I. The upper surface of the head 24a of the nut 24 is providedwith the circular bead 24b adapted to embed itself into the gasket 240.

The numeral 28 indicates as a whole a fuse Q plug carried by the coverll. Said fuse plug includes the fusible element 21 mounted within theplug member 28, which plug member 28 is externally screw-threaded and isadapted to be mounted within a correspondingly tapped hole The plugmember 28 is provided with the "head 2911, by means of which the fuseplug 26 maybe screwed tightly into position. The tapped hole 28 istapped only at its 1 lower end, and the plug member 28 isthreaded onlyadjacent to the head 29a, and accordingly it is impossible to screw inthe fuse plug 26 from the wrong direction. A gasket 38 is providedbetween the head 28a and the cover H for providing a tight joint. Theupper surface of the head 23a. will be provided with an annular beadcessive tightening efiort' on 28b which will become embedded in thegasket,

38 to provide a tight seal without requiring exsaid plug 26. As clearlyshown in Figure 3, the fusible element 21 is tapered, the largerextremity thereof being 5 uppermost. By reason of this construction, inthe event that an excessive temperature is developed in the cooker, thefusible element 21 will first soften and be released from the plugmember 28, permitting the escape of steam from with- 10 in the vesselI0. By reason of this construction the melting of the fusible element 21is avoided. The numeral 3| indicates a shield covering the upperextremity of the hole 28. Said shield isreleasably held in position bymeans of the spring 15 23 and is releasably held relative to the hole 23by a pair of struck out portions 32-32 adapted to seat withincorresponding recesses in the upper side of the cover II. By reason ofthe shield 3|, in the event that the fusible element 21 is re- 20leased, juices and other fluid materials within the vessel I8 will beprevented from spurting over the region adjacent to the vessel in, butwill be deflected and merely flow downwardly on the cover II and alongthe sides of the vessel It. 85

As shown in Figures 1 and 2, the vessel It) may be provided with a pairof handles 33-33, which may be of heat insulating material, each of saidhandles being supported by a pair of lugs 34-34 integral with the vessell8. At the two ends of each of the handles 33-33 on the inner sides ofthe lugs 34-34 are the guard disks Mat-34a of heat insulating material,which protect the hands of the'operator from contact with the hot metallugs 34-34. 35

The numeral 35 indicates as a whole ,a valve, which forms a veryimportant part of the'present invention. Under normal operation thevessel ID with its cover ll form a tightly sealed enclosure,

steam generated therein being prevented from,

escape except through said valve.

The valve in the illustrated embodiment of the present inventionincludes the stem 38 having the reduced threaded end portion :31. Saidthreaded end portion 31 is adapted to project through an opening 38 inthe cover- H. .Said

valve stem 36 including its reduced end portion 31 has tight sealingengagement with thecover I J ll, whereby no fluid may escapetherebetween.

Preferably said stem'36 will be so tightly secured to the cover II thatit will not be removable by the user, so that no difilcu lties will beencountered in service by leakage around said stem. The stem 36 isprovided with the axial bore 39, the lower extremity of which is reducedin diameter to provide a valve seat 40. The upper portion of the stem 36is internally screw-threaded for the reception of thenut provided withthe depending skirt 42, which nut 4| and skirt 42 provide an elongatedbearing for' the longitudinally reciprocable valve member '43. Saidvalve "member 43 is adapted to seat by gravity in the valve seat 48,thereby controlling communication between the interior of the vessel l8and the outside atmosphere. The lower extremity' of the bore 33 u may beprotected by the screen 44, which screen is mounted within the nut 45adapted to have a bifurcated end. One of the bifurcations, in-

dicated by the numeral 49, seats under the head 45 of the valve member43. The other of said bifurcations, indicated by the numeral 50, is 5adapted to be engaged by the valve member 43 when said valve member israised by steam pressure within the cooker. Said bifurcation 50 is alsoadapted to engage under a struck out portion 5| of a leaf spring 52secured to said valve 10 stem 35. Said lever 41 is swingingly mountedupon the valve stem 36 by means of the pin 53. Said pin 53 isprovided'with the knurled bead 53a and an adjacent threaded portion 53bthreaded into the adjacent part of the stem 35. 15 The distant extremityof thepin 53 acts merely as a pilot pin. By reason of this construction,it the pin 53 should be broken, no difficulties will be encountered inreplacing said pin. The leg 48a of the lever is threaded for thereception of a weight 54 which is provided with a threaded hole. Theouter extremity of the leg 48a is provided ,with the cross pin 55 forpreventing the escape of the weight 54 from said leg 48a. Said leg 45ais provided with indicia disposed along 25 its length acting as markersfor positioning the weight 54.

Mounted upon the valve stem 35 and having communication with the axialbore 39 thereof is the assembly 55, which includes a warning 30 whistleand also a relief valve. Said assembly includes the externallyscrew-threaded stem 56 threaded into the valve stem 36, which stem 56 isprovided with the bore51. Said assembly 55 is.

also provided with v the upstanding externally. 3 screw-threaded stem 58provided withthe axial bore 58. Said-stem 53"provides a seat. for theball valve 60'. f -fiousingsaid-ball "valve 50 is the cap. 5i}:-'intemallyiscrewgthreaded to cooperate j withthe external"s"crew.-threads'of the stem 58. 4o Saidcapiliis provided-witlrltheapertures 52-62. 'I'hreade' jin tjo ',.;th stung is the whistle 63,"jwhichniaytak i f0 mation' of whistles well whistle 53 provides a tweentheinterior of andon; the-then the-above described ll as followsiTheroperator of the cooker will place v recesses andturning the handle;,thereby s'winglngjthe extremities of the Spring igpqabove .the raisedsurfaces 21-21 ,until said l'extreinities abut against the] abutments'ZL- H. tin ie j to turn the handle I41 61 the cover -i l wlth its"v The;operator will scan agenient-iwithjthe under theturnin'g or Lathe,vessel-J0. An easy fit my be,provide dv or'saidicoverrial within thevessel Ill. The operaton will then place the vessel upon a source ofheat" and will'adiiistthe el ibnship between ent.ofF-thepresent.invention is substanthe imaterialsito be? cooked within the essel Itand'iwill' then insert the, cover fitting 'ianfce's l6 and I1withintheireor- .danger of' slippage.

cided advantage that after the materials to be cooked have beensubjected to the desired pressure for the desired period of time, thesteam may be positively and completely released, to the 65 end that thecover may be readily removed from the the vesselefvessel Hi. By reason75 weight 54 to a predetermined positionon thelever' arm 41. As pointedout above, the leg 43a of said lever arm 41 will calibrated'with indiclawhereby the operator may so place the weight 54 as to cause the valvemember 43 to lift when a predetermined pressure is reached within the Icooker.

As the temperature rises within the cooker, steam will be generatedwithin the vessel l0 until the pressure thereof is suflicient to forceupwardly the valve member 43. Upon the attainment of such pressure, thehead 45 of said valve member 43 will engage the under side of thebifurcation 50 of the lever 41, swinging said lever about the axis ofthe pin 53. Under these circumstances steam will escape past the valvemember 43 into the assembly 55. Part of said steam will escape throughthe whistle 53, giving a warning to the operator. In the event of excesssteam pressure within the vessel ID, the ball valve 60 will be raised,thereby limiting the pressure upon the whistle 53 and maintaining thepressure upon said whistle 63 at such a value that it will operateefliciently. According to practice which is at present preferred, theoperator, when the first warning has 5 been sounded by the whistle 63,will turn the weight 54 out to the extremity of the leg 48a of the lever41, whereby the effect of said weight 54 will be a maximum. The operatorat this time will remove the cooker from the source of heat.

lifting the valve member 43 by reason of the engagement of thebifurcation 49 under the head 46 of said valve member 43.. The valvemember l 43 will be held in its position, permitting the escape of steamfrom within the cooker.

' dicated above, the provision of the ball valve 80 As inwill preventthe application of excessive pressure tothe whistle 53 and will limitsaid pressures to those which will produce the desired tone in saidwhistle 63. When the steam has escaped from v the cooker, the cover llmay be readily removed I by backing off the tension on the spring20,1owv ering the cover slightly and swinging it to allow 55 passage ofsaid cover through the elliptical opening in the vessel Ill. By reasonof the fact that the weight 54 is threaded upon the leg 48a of the lever41, a posi-' tive setting of said weight 54 may be had without 00 Thespring 52 has the de- The provision of the ball valve has the ad-.vantage that the whistle 63 maybe small enough "to operate?onjlowpressures but will be protected against excessive pressures. Itneed not be explainedthat: the ordinary whistle willinot operateproperly at both low and high pressures. The a ball valye 53' has thefunction of maintainin as to expedite the release of-pressure within thecooker when the operator desires to open the cooker.

The operator of the cooker, either by reading instructions or byexperience, will know that when she sets the weight indicia on the leg48a, the valve member 43 should lift in a certain number-of minutes toproduce the desired results. If the thermometer 8| indicates that thetemperature (and consequently the pressure) within the closed cooker isrising too slowly or too rapidly, the operator will adjust the. sourceof heat accordingly to efi'ect the accomplishment of the desiredpressure (and tem-' perature) at the end of the proper length of time.Moreover, it is frequently desirable to hold a pressure within thecooker for a predetermined length of time after said pressure has beenattained. The operator may tum'the weight out toward the outer end ofthe leg 48a, and, observing the thermometer 64, she may adjust thesource of heat to maintain said pressure.

The fuse plug may be screwed into the cover I I only from the bottomthereof. Therefore it is impossible to insert s'aid fuse plug inthe'wrong direction. By reason of'the fact that the fusible element 21thereof is larger at its upper extremity than at its lower extremity,said fusible element will soften from the plug 28 and blow upwardlybefore it will melt, thereby preventing the running of the fusibleelement into the cooker. By reason of the guard 3|, protection is hadagainst the spraying of the contents of the cooker around the vicinityif and when the fusible element 21 becomes loosened by excessivetemperatures.

By reason of the protuberances I8 and I! at the ends of the cover I I,jamming of the cover is prevented, which jamming might otherwise preventthe, ready opening of the cover after the cooking operation has beenaccomplished. By reason of the interfltting of said protuberances l6 andi1 within their corresponding recesses,

the advantage is had that a slight amount of play may be provided allaround the cover in a plane at right angles to the axis of said cover.It may be explained that if the stud I 8 be entered into the ,nut 2| ina fashion to cross or strip the threads, one or both'of the members l8and 24 are liable to be destroyed. It is preferred to make the nut 24 ofsofter metal than the stud l8 so that said nut (being comparativelyinexpensive) will be the one to be damaged rather than the moreexpensive stud I 8 with its handle it. The result is attained that inthe event of misuse of the stud l8 in connection with the nut 24 arepair job will involve only the-removal and replacement of theinexpensive nut 24.

The beads Ila, 24c and no will not only embed themselves into theadJacent portions of .their respective gaskets, but will compress theother sides of said gaskets into tight engagement with their respectiveabutment, providing eflective sealing areas. As explained above, thebead lla upon the flange ll of the cover H has the very importantfunction of forming a more or less permanent set in the gasket l5,insuring the replacement of said gasket always in the same positionrelative to the flanges I 3 and I4, thereby preventing leakage whichmight otherwise occur when said gasket loses some of its originalresiliency. I

Though a preferred embodiment of the present invention has beendescribed in detail, many modifications will occur to those skilled inthe 54 at any one of the I rim portions having a continuous beadengaging art. It is intended to cover all such modifications that fallwithin the scope of the appended claims.

What is claimed is- I. In combination, a said cover having alongitudinal axis longer than the cross axis thereof, said cover havinga rim adapted to exert pressure against the inner surface of saidvessel, a gasket between said rim and said inner surface, said cover,said vessel having cooperating radially extending protuberances andrecesses located at spaced re.- gions relative to the outline of saidcover for preventing jamming of said cover withinsaid vessel, theprotuberances and recesses at one of said 15 regions differing inoutline from the protuberances and recesses at the other of saidregions.

2. In combination, a vessel, a cover therefor, said cover having a rimportion. said vessel having a rim portion, the rim portion of said coverbeing adapted to exert pressure against the inner surface of the rimportion of said vessel, holding means for holding said cover in closingrelation! ship with respect to said 'vessel, and a gasket positionedbetween said rim portions, one of said one surface of said gasket andadapted to embed itself into said gasket for improving the sealingfunctions thereof, said gasket and said rim portions having cooperatingprotuberances and recesses located at spaced regions relative to the.outline of said cover, said protuberances and recesses at one of saidregions differing in outline from the protuberances and recesses attheother of said regions.

3. In combination, a vessel, a cover therefor, said cover having a rimportion, said vessel having a rim portion, the rim portion of said coverbeing adapted to exertpressure against the inner surface of the rimportion of said vessel, holding 40 means for holding said cover inclosing. relationship with respect to said vessel, and a gasketpositioned between said rim portions, one of said rim portions having acontinuous bead engaging one surface of said gasket and adapted to embed4,5

itself into said gasket for improving the sealingfunctions thereof, saidcover, said vessel and said gasket having cooperating protuberances andrecesses located at spaced regions relative to the outline of saidcover, said protuberances and re- 5 cesses at one of said regionsdiffering in outline from said protuberances and recesses at the otherof said "regions for insuring a predeterminedlocation of said vessel,cover and gasket relative to one another.

4. In combination, a vessel, 9. cover therefor, said cover having alongitudinal axis longer than thecross-axis thereof, said cover having arim portion, said vessel having a rim portion, the rim portion of saidcover being adapted to exert pres- 0 sure against the inner surface ofthe rim portion of said vessel, a gasket between said rim portions, saidcover, said vessel and said gasket having cooperating radially extendingprotuberances, and

recesses located at spaced regions relative to the 5 t 1 outline of saidcover, said protuberances and recesses at one'of said regions differingin outline from said protuberances and recesses at the other of saidregions for insuring predetermined rela tionship between said cover,said vessel and said 70 gasket and for preventing Jamming of said coverwithin said vessel.

5. In combination, a vessel, a cover therefor,

said cover having a longitudinal axis longer than" the cross-axisthereof. said cover having a rim 15* vessel, a cover therefor, '6

said gasket and 10 portion, said vessel having a rim portion, the rimportion of said cover being adapted to exert pressure against the innersurface of the rim portion of said vessel, a gasket between said rimportions, said cover, said vessel and said gasket having cooperatingradially extending protuberances, and recesses located at spaced"regions relative to the outline of said cover, said protuberances andrecesses at one of said regions differing in outline from saidprotuberanees and recesses at the other of said regions for insuringpredetermined relationship between said cover, said vessel and saidgasket and for preventing jamming of said cover within said vessel,one'of said rim portions having a continuous bead positioned to engage asurface of said gasket for improving the sealing functions of saidgasket.

ERIK G. GRUNDSTROM.

